1. Technical Field
Exemplary embodiments of the present invention relate to detecting a touch position, and more particularly, exemplary embodiments of the present invention relate to a method of detecting touch positions, a touch position detecting apparatus for performing the method and a display apparatus having the touch position detecting apparatus.
2. Discussion of the Related Art
A touch panel is an example of input devices which serve as an interface between an information communication apparatus having a display and a user. The user touches the touch panel with a finger or a stylus and the information communication apparatus may then interpret the touches as input.
A touch panel may serve as an intuitive way for people of all ages to interact with a computerized device. Thus, touch panels are commonly used in cellular phones, personal digital assistants (PDAs), informational kiosks and automated teller machines (ATMs), for example, as may be found in a bank, a public office, a medical center and a tourist center, a direction board, etc. Touch panels may be incorporated into flat panel displays such as a liquid crystal display (LCD) apparatus or conventional display devices such as those having a cathode ray tube (CRT).
The touch panel may be classified as a resistive/pressure sensitive type touch panel, a capacitive/electrostatic type touch panel, an infrared type touch panel and so on.
For example, the infrared type touch panel uses characteristics of light to determine when a touch is present. In the infrared type touch panel, infrared light is blocked by an obstacle disposed on a surface of the touch panel so that a touch position may be detected. In the infrared type touch panel, beams of infrared light propagating in a horizontal direction and in a vertical direction are respectively blocked so that the touch position is detected by reading x and y coordinates of a position at which the infrared light is blocked.
A first side of the infrared type touch panel includes infrared light sources that radiate infrared light and a second side of the infrared type touch panel includes a set of infrared light sensors that detect the infrared light. Accordingly, an infrared grid is established on the surface of the touch panel.
However, in conventional infrared type touch panels, even though a number of infrared light sources may be used, the panel may be limited to only sensing one touch position at a time. Accordingly, when two positions are touched on the infrared type touch panel at the same time, the infrared type touch panel may not distinguish two positions, the infrared type touch panel may detect only the previously touched position, or a ghost touch position is detected and a touch error may occur.